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Related papers: Tests of Loop Quantum Gravity from the Event Horiz…

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A mathematically consistent rotating black hole model in loop quantum gravity (LQG) is yet lacking. The scarcity of rotating black hole solutions in LQG substantially hampers the development of testing LQG from observations, e.g., from the…

General Relativity and Quantum Cosmology · Physics 2023-01-25 Shafqat Ul Islam , Jitendra Kumar , Rahul Kumar Walia , Sushant G. Ghosh

The Event Horizon Telescope (EHT) observation unveiled the first image of supermassive black hole Sgr A* showing a shadow of diameter $\theta_{sh}= 48.7 \pm 7\,\mu$as with fractional deviation from the Schwarzschild black hole shadow…

General Relativity and Quantum Cosmology · Physics 2022-11-10 Rahul Kumar Walia , Sushant G Ghosh , Sunil D Maharaj

The Event Horizon Telescope (EHT) has provided a new tool for testing the strong-field regime of gravity by imaging the shadows of M87* and Sgr A*. These observations provide the first real opportunity to test whether quantum…

General Relativity and Quantum Cosmology · Physics 2026-05-29 Heena Ali , Sushant G. Ghosh

Horizon-scale images of black holes (BHs) and their shadows have opened an unprecedented window onto tests of gravity and fundamental physics in the strong-field regime. We consider a wide range of well-motivated deviations from classical…

The Event Horizon Telescope (EHT) recently released an image of the supermassive black hole Sgr A* showing an angular shadow diameter $d_{sh}= 48.7 \pm 7\,\mu$as and Schwarzschild shadow deviation $\delta =…

General Relativity and Quantum Cosmology · Physics 2023-02-28 Sushant G. Ghosh , Misba Afrin

The Event Horizon Telescope (EHT) has guided strong-field gravitational physics by providing the first direct images of the supermassive black holes M87* and Sagittarius A*. The EHT observations offer unprecedented opportunities to test…

General Relativity and Quantum Cosmology · Physics 2026-04-16 Towheed Ahmad Nengroo , Shafqat Ul Islam , Sushant G. Ghosh

The scarcity of quantum gravity (QG) inspired rotating black holes limits the progress of testing QG through Event Horizon Telescope (EHT) observations. The EHT imaged the supermassive black holes, Sgr A* and M87*, revealing an angular…

General Relativity and Quantum Cosmology · Physics 2025-04-30 Heena Ali , Shafqat Ul Islam , Sushant G. Ghosh

The Event Horizon Telescope (EHT) collaboration unveiled event-horizon-scale images of the supermassive black holes (SMBHs) M87* and Sgr A*, revealing a dark brightness depression, namely the black hole shadow, whose shape and size may…

General Relativity and Quantum Cosmology · Physics 2023-07-27 Misba Afrin , Sushant G. Ghosh

The half opening angle of a Kerr black-hole shadow is always equal to (5+-0.2)GM/Dc^2, where M is the mass of the black hole and D is its distance from the Earth. Therefore, measuring the size of a shadow and verifying whether it is within…

High Energy Astrophysical Phenomena · Physics 2015-12-02 Dimitrios Psaltis , Feryal Ozel , Chi-Kwan Chan , Daniel P. Marrone

The linear-quadratic Generalized uncertainty principle (LQG) is consistent with predictions of a minimum measurable length and a maximum measurable momentum put forth by various theories of quantum gravity. The quantum gravity effect is…

General Relativity and Quantum Cosmology · Physics 2026-01-01 Sohan Kumar Jha

The Event Horizon Telescope (EHT) has recently observed the image and shadow of the supermassive compact object Sagittarius A$^*$ (Sgr A$^*$). According to the EHT collaboration, the observed image is consistent with the expected appearance…

General Relativity and Quantum Cosmology · Physics 2023-05-29 Rajibul Shaikh

In this study, we delve into the observational implications of rotating Loop Quantum Black Holes (LQBHs) within an astrophysical framework. We employ semi-analytical General Relativistic Radiative Transfer (GRRT) computations to study the…

General Relativity and Quantum Cosmology · Physics 2023-12-29 Hong-Xuan Jiang , Cheng Liu , Indu K. Dihingia , Yosuke Mizuno , Haiguang Xu , Tao Zhu , Qiang Wu

Astrophysical black holes are expected to be described by the Kerr metric. This is the only stationary, vacuum, axisymmetric metric, without electromagnetic charge, that satisfies Einstein's equations and does not have pathologies outside…

High Energy Astrophysical Phenomena · Physics 2023-11-17 The Event Horizon Telescope Collaboration

Recently, the Event Horizon Telescope (EHT) achieved the realization of an image of the supermassive black hole $\textrm{Sgr~A}^\star$ showing an angular shadow diameter $\mathcal{D}= 48.7 \pm 7\mu as$ and the fractional deviation…

General Relativity and Quantum Cosmology · Physics 2024-04-23 L. Chakhchi , H. El Moumni , K. Masmar

Our Galactic Center, Sagittarius A* (Sgr A*), is believed to harbour a supermassive black hole (BH), as suggested by observations tracking individual orbiting stars. Upcoming sub-millimetre very-long-baseline-interferometry (VLBI) images of…

The Event Horizon Telescope (EHT), a global submillimeter wavelength very long baseline interferometry array, unveiled event-horizon-scale images of the supermassive black hole M87* as an asymmetric bright emission ring with a diameter of $…

General Relativity and Quantum Cosmology · Physics 2020-05-12 Rahul Kumar , Sushant G. Ghosh

We investigate Einstein-\AE ther gravity in light of the recent Event Horizon Telescope (EHT) observations of the M87*. The shape and size of the observed black hole shadow contains information of the geometry in its vicinity, and thus one…

General Relativity and Quantum Cosmology · Physics 2021-05-20 Mohsen Khodadi , Emmanuel N. Saridakis

In general relativity, the angular radius of the shadow of a black hole is primarily determined by its mass-to-distance ratio and depends only weakly on its spin and inclination. If general relativity is violated, however, the shadow size…

We investigate gravitational lensing in the strong deflection regime by loop quantum gravity (LQG)-motivated rotating black hole (LMRBH) metrics with an additional parameter $l$ besides mass $M$ and rotation $a$. The LMRBH spacetimes are…

General Relativity and Quantum Cosmology · Physics 2023-10-31 Jitendra Kumar , Shafqat Ul Islam , Sushant G. Ghosh

The Event Horizon Telescope (EHT) collaboration has recently released the first image of a black hole (BH), opening a new window onto tests of general relativity in the strong field regime. In this paper, we derive constraints on the nature…

General Relativity and Quantum Cosmology · Physics 2020-02-24 Cosimo Bambi , Katherine Freese , Sunny Vagnozzi , Luca Visinelli
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